core.formatters

Built-in formatters

DefaultLLMFormatter formats:

• PromptEvent
• LLMEvent
• ToolEvent
• (optionally) StepEvent end/error events for compact logs

It truncates long text and argument blobs to keep console output manageable.

Custom formatting

You can create your own formatter by implementing:

def format(self, event) -> str | None:
    ...

Then plug it into a sink (or into the base PerTypeFormatter pattern) as part of your tracer configuration.

Next steps

Observability guide

How to wire formatters into sinks and production logging.

base.tracing reference

The sink/formatter interface surface and tracer configuration.